phase.name: Experiment phase ("T1", "T2", "T3", "T4", "T5"). Note 1: In one session
for Bird 2, and one session for Bird 4, the T3 procedure was accidentally run
during another phase - phase.name is set to 'ErrorT3' for these sessions.

date: Date of session (in YYYY-MM-DD format)

time: 1 = first session on that date, 2 = second session on that date.

sess: Session number (resets for each phase)

trial: Trial number (resets for each session). Note 2: A few sessions have fewer trials than
expected - this is due to birds occasionally ceasing to peck before session end. Note 3: A few
sessions have more trials than expected - this is due to experimenter error. These sessions
contain the appropriate trial types for the phase, just slightly too many of them.